Thousands of Haitians outraged over what they claim was a rigged election are rioting in the streets of the capital and have set fire to the party offices of one of two presidential candidates that made it to a runoff.

The results of the Nov. 28 presidential election, announced Tuesday, saw popular candidate Michel "Sweet Micky" Martelly fall less than 1 percentage point behind Jude Célestin, the government-endorsed candidate.

The international airport in Port-au-Prince was shut down and schools and businesses were shuttered today as Mr. Martelly's supporters erected burning barricades in the streets and set fire to government offices in the capital and other cities. The Associated Press reports that the Unity party headquarters, the center of Celestin's campaign, was ablaze for an hour today.

Riot police prevented protesters from attacking the office of the Provisional Electoral Council (CEP), which delivered the election results Tuesday night. Ms. Manigat garnered 31.37 percent of the vote in the first round, Célestin took 22.48 percent, and Martelly took 21.84.

Manigat was expected to take the most votes. But in a surprise, Célestin surged into second place despite a weak showing in exit polls.

Supporters of Mr. Martelly, who was widely predicted to make it into the final race, quickly took to the streets in protest last night, reportedly setting up burning barricades. Other protests and gunfire were reported Tuesday night in various parts of the capital, Port-au-Prince, and rioting continued into Wednesday.

International electoral observers had said that they found no evidence of widespread fraud in the days following the poll, but the US embassy in Port-au-Prince issued a statement Tuesday that it was concerned about electoral results that were “inconsistent.”

“The United States, together with Haiti's international community partners, stands ready to support efforts to thoroughly review irregularities in support of electoral results that are consistent with the will of the Haitian people expressed in their votes,” the statement read.

The Nov. 28 vote was marred by accusations of fraud, including that many voters were turned away at the polls. Twelve of 19 candidates on the ballot declared fraud, including Martelly and Manigat, saying that the administration of President René Préval was rigging the ballot in favor of Célestin, the former head of the government reconstruction agency and the president's handpicked successor. The CEP itself has also come under scrutiny in recent months for its close ties to Mr. Préval.

Préval took to the radio today to call for calm. "This is not how the country is supposed to work," he said. "People are suffering because of all this damage."

He also criticized the United States for interfering with the poll, saying "the American Embassy is not the CEP."

Candidates have 72 hours to file appeals against the results, which could lead to uncertainty in the days ahead in this troubled country, still reeling from the Jan. 12 earthquake and now an outbreak of cholera.

"Haiti is set up for a government that does not have popular support. In the next five years [the government] will have to make a lot of hard decisions, they will have to induce the population to make many sacrifices, and the only way you can do that is to have popular trust or to use force," says Mr. Concannon.

Some have criticized Haiti for moving forward with the vote, despite all the troubles it faces. But many in the international community said that holding elections as planned was essential to bringing normalcy back to the country as soon as possible.